Lighting systems of today use occupancy detection and advanced control systems with predefined detection zones and lighting zones. FIG. 1 gives an example of an existing lighting system with occupancy detection. The system comprises a plurality of controllers 10, 20 each comprising a respective presence sensor in the form of an occupancy sensor, and a plurality of lighting devices in the form of luminaries 1.1 . . . 2.6. The luminaires are grouped into different lighting zones, and the luminaires of each lighting zone are connected to a respective one of the controllers to be controlled based on its respective occupancy sensor. Each controller 10, 20 is connected to a power supply 32 (e.g. mains power supply) and may be connected to supply power onwards to the luminaires of its respective group as and when required. In the illustrated example, a first group of luminaires 1.1 . . . 1.6 is connected to be controlled by a first controller 10 based on a first occupancy sensor, and a second group of luminaires 2.6 is connected to be controlled by a second controller 20 based on a second occupancy sensor. For example, the luminaires may be mounted on the ceiling and/or walls of an indoor space such as an office space, and the different lighting groups may correspond to different rooms and/or different regions of a room. The number of luminaires and groups and their locations may be arranged as desired depending on the application in question.
Each controller's occupancy sensor is arranged to detect presence of an occupant 30 (typically a human) when in that sensor's respective detection zone, e.g. based on known infrared or ultrasound sensing techniques. The sensor is arranged so that its detection zone services the lighting zone of the respective group of luminaires. When occupancy is detected by the sensor of one of the controllers 10, 20 in a given detection zone, the controller controls all the luminaries of that group to turn on. In detection zones where occupancy has not been detected on the other hand, the respective controller keeps all the luminaires of its group turned off. For example in FIG. 1, an occupant 30 is detected by the occupancy sensor of the first controller 10 to be in the detection zone corresponding to the first group of luminaires 1.1 . . . 1.6, and the first controller 10 turns on all the luminaires of that group with a uniform illumination (e.g. each at 60% of maximum output). But in the detection zone corresponding to the second group of luminaires 2.1 . . . 2.6, the occupancy sensor of the second controller 20 has not detected an occupant and so the second controller 20 keeps the luminaires of that group completely switched off.